Scientists wanted to see if increasing the levels of ketones—a type of fatty acid—in mice could boost the production of a protein called SIRT3. This protein is thought to protect neurons.
As the brain starts to be affected by Alzheimer’s disease, the way some mitochondria—the powerhouses of cells—work is thought to be damaged, as are some brain cell networks, the authors explained in the Journal of Neuroscience.
The team studied mice with Alzheimer’s disease—including some who had been genetically modified to have lower than normal levels of SIRT3—as well as regular mice who acted as controls.
Mice with lower levels of SIRT3 were more likely to die prematurely and have seizures. Certain types of interneurons—brain cells that transmit impulses—were also found to be more likely to die in these mice, when compared with the rodents with just Alzheimer’s disease and controls.
When researchers supplemented the mice’s diets with ketones, which boosted SIRT3 levels, the animals had fewer seizures, lived longer and their interneurons appeared to be preserved.
The team concluded the ketone supplements appeared to help SIRT3 preserve the interneurons, and protect brain circuits against becoming over-excited in what is known as hyperexcitability.
Study co-author Aiwu Cheng, a researcher at the National Institutes of Aging, told Newsweek efforts to understand the development of Alzheimer’s have focused on the build-up of a toxic compound called amyloid-beta in the brain. But scientists believe that, perhaps even before a person’s cognition suffers, brain regions might undergo what is known as “neuronal network hyperexcitability.”
Cheng said eating foods containing the specific ketone supplement given to mice provides a “good example” that increasing SIRT3 levels “may offer a promising therapeutic target for protecting against age-related cognitive decline and Alzheimer’s disease.”
Co-author Todd M. King, of the National Institute on Alcohol Abuse and Alcoholism, explained to Newsweek no specific foods contain ketones in amounts that are physiologically or medically relevant. But some foods contain compounds that, when metabolized, can be converted into ketones, such as some mid-chain triglycerides. However, these foods raise blood ketones only modestly and may bring with them some undesirable side effects, especially with regard to circulating triglycerides and cholesterol.
Cheng and co-author Richard L. Veech, of the National Institute on Alcohol Abuse and Alcoholism, said “blood ketone levels can be increased through intermittent fasting and exercise regimes. This study adds to the data that supports these healthy lifestyle interventions may be beneficial in terms of long-term neurological health.”
“People could consume MCT oils but these will only be converted to ketones during fasting,” they said.
“The brain hyperexcitability is linked to many brain disorders, the implication of this study is not limited to Alzheimer’s disease,” the pair added.
However, Cheng stressed: “This study was performed in a mouse model, and although it is very promising, we need to exercise caution when extending the results to human subjects.
Experts who didn’t work on the study urged members of the public to approach the findings with caution, and highlighted known ways to prevent the condition that 5.8 million Americans live with.
Dr. Katy Stubbs Alzheimer’s Research UK told Newsweek: “Many studies have tried to tie particular diets or a specific food with better brain health.
“This is early-stage research so we cannot reach any firm conclusions about how ketone supplements might affect the development of diseases like Alzheimer’s or the symptoms of dementia in people.
“What we do know is that eating a balanced diet, as part of a wider healthy lifestyle, is important to keep our brains healthy as we age. A healthy lifestyle includes staying physically active, eating a healthy diet, only drinking within recommended guidelines, not smoking and keeping blood pressure and cholesterol levels in check.”
Hannah Churchill, research communications officer at the Alzheimer’s Society, told Newsweek: “While this study in mice provides more evidence that a ketogenic diet could help protect brain cells, by counteracting damage to the cells’ energy-producing batteries, we are still far from being able to say a ketogenic diet prevents Alzheimer’s disease.
“It’s very early days, and this effect has yet to be tested robustly on humans. We need more research including high-quality trials to measure the impact of a low-carb, high-fat diet on nerve cells as well as memory and thinking skills,” said Churchill.
